According to another embodiment of the process of the present invention, camptothecin derivatives of the general formula: ##STR8## wherein Y' is OH or the grouping OR3 where R3 is a lower alkyl group or an acyl group and Z is H or an acyl group, as well as water-soluble alkali metal salts are prepared by treating camptothecin with sulfuric acid and a persulfate in an aqueous medium containing a tr